Perceptual learning: stimulus-specific learning from low-level visual plasticity?

A new study has found that changes in visual cortical processing account for behavioral perceptual learning, supporting the idea that stimulus-specific learning can result from low-level visual plasticity.     

Visual system: how is the retina wired up to the cortex?

A single retinal output neuron transmits to primary visual cortex through multiple pathways with different strengths. A new study in which activity was simultaneously recorded in pairs of retinal and cortical neurons provides evidence that these pathways converge on a single cortical neuron.     

Estimating maturity from size-at-age data: Are real-world fisheries datasets up to the task?

Reviews in Fish Biology and Fisheries - The size and age at which individuals mature is rapidly changing due to plastic and evolved responses to fisheries harvest and global warming. Understanding...     

Sequence learning: what's the hippocampus to do?

The medial temporal lobe is crucial for some forms of memory, but its role in implicit learning has remained in question. A brain imaging study by Schendan et al., in this issue of Neuron, provides direct evidence of medial temporal lobe activation during implicit learning of motor sequences.     

Motor learning: spare the rod to benefit the child?

A new study has found that individuals who were rewarded while they learned a motor task performed it much better one month later than those who were punished or received nothing. Long-term memories depend on events experienced during learning.     

Lung Cancer: Are we up to the Challenge?

Lung cancer is the leading cause of cancer deaths worldwide among both men and women, with more than 1 million deaths annually. Non-small cell lung cancer (NSCLC) accounts for about 80% of all lung cancers.Although recent advances have been made in diagnosis and treatment strategies, the prognosis of NSCLC patients is poor and it is basically due to a lack of early diagnostic tools.However, in the last years genetic and biochemical studies have provided more information about the protein and gene's mutations involved in lung tumors. Additionally, recent proteomic and microRNA's approaches have been introduced to help biomarker discovery.Here we would like to discuss the most recent discoveries in lung cancer pathways, focusing on the genetic and epigenetic factors that play a crucial role in malignant cell proliferation, and how they could be helpful in diagnosis and targeted therapy.     

Perceptual learning and sensomotor flexibility: cortical plasticity under attentional control?

Recent research reveals long-lasting cortical plasticity of early sensory cortices even in adults. Sensory signals could be modified under top-down control if necessary quite early in order to optimize their signal-to-noise ratio, leading to 'low level' or 'early' perceptual learning (PL). For easy tasks, such elaborate top-down influences are usually not required, and learning is restricted to late selection of the appropriate signals on higher cortical levels, which seems easier and faster to achieve. But to reach the absolute limits of sensory performance, PL seems to optimize the entire chain of sensory processing. Hence, improvement for these extreme perceptual abilities is quite specific for a number of stimulus parameters, such as the position in the visual field and sometimes even the trained eye, reflecting the specificity of receptive fields in early sensory cortices. Early PL may be just one example--even if a very extensive one--of the mechanisms of neuronal plasticity and sensomotor flexibility that are constantly updating our sensomotor representations as a result of experience. As an illustration, this review contains some new experimental results on PL and sensory flexibility in the context of adaptation to multifocal intraocular lenses.     

Are legislative frameworks in Canada and Ontario up to the task of addressing invasive alien species?

As a signatory to the international Convention on Biological Diversity (CBD), Canada has committed to prevent, control, and eradicate invasive alien species (IAS). Yet, despite developing policy on biodiversity and IAS, the federal government has been criticized for its inaction on biological invasions over the past decade. In Canada’s most populous province, Ontario, similar concerns have been raised about the provincial government’s approach to dealing with IAS. The ongoing criticism of government response suggests that an effective legislative framework to guide and coordinate action on IAS may be lacking in Canada. In this paper, we examined how well existing legislation at the federal and Ontario levels addresses IAS threats, and thus contributes to CBD commitments. We reviewed a total of 98 pieces of legislation, comprised of 55 federal acts, two federal omnibus bills, and 41 Ontario acts. Of these, 20 federal and 12 Ontario acts were found to cover IAS either intentionally or incidentally, but IAS was not the central focus of most legislation. No consistent terminology existed across legislation referring to IAS, further highlighting a lack of focus on the issue. Legislation on IAS was administered by several different ministries both federally and in Ontario, but coordination of action among agencies was not explicitly addressed in laws and regulations. While many acts provided broad powers of enforcement, most provisions were not directly linked to IAS prevention and management. In general, Canada’s legislative framework on IAS is fragmented, and this complicates the development of a coordinated approach to the problem.     

How Much Gravity Is Needed to Establish the Perceptual Upright?

Might the gravity levels found on other planets and on the moon be sufficient to provide an adequate perception of upright for astronauts? Can the amount of gravity required be predicted from the physiological threshold for linear acceleration? The perception of upright is determined not only by gravity but also visual information when available and assumptions about the orientation of the body. Here, we used a human centrifuge to simulate gravity levels from zero to earth gravity along the long-axis of the body and measured observers'' perception of upright using the Oriented Character Recognition Test (OCHART) with and without visual cues arranged to indicate a direction of gravity that differed from the body''s long axis. This procedure allowed us to assess the relative contribution of the added gravity in determining the perceptual upright. Control experiments off the centrifuge allowed us to measure the relative contributions of normal gravity, vision, and body orientation for each participant. We found that the influence of 1 g in determining the perceptual upright did not depend on whether the acceleration was created by lying on the centrifuge or by normal gravity. The 50% threshold for centrifuge-simulated gravity''s ability to influence the perceptual upright was at around 0.15 g, close to the level of moon gravity but much higher than the threshold for detecting linear acceleration along the long axis of the body. This observation may partially explain the instability of moonwalkers but is good news for future missions to Mars.     

Do chimpanzees cooperate in a learning task?

The aim of this study was to assess the ability of chimpanzees (Pan troglodytes) to cooperate in an instrumental task. A specially constructed fruit distributor was presented to a group of six captive chimpanzees. A cooperative response required two chimpanzees: both had to pull a handle simultaneously to make a fruit fall into the cage. The dominant male of the group and an infant produced most of the operant responses, and the male got nearly all the fruits. Other conspecifics avoided the dominant male at the apparatus. Social influences appear to limit the possibility of co-operation between individuals because a certain level of interindividual tolerance is required. The results revealed a significant increase in the number of pulls each time both chimpanzees were together at the apparatus. Operant chimpanzees learn to coordinate their actions in time and space.     

Too much teaching, not enough learning: what is the solution?

The curriculum is packed with so much content that teachers resort to telling students what they know and students simply commit facts to memory. The packed curriculum leaves little time for students to acquire a deep understanding of the subject or to develop life-long skills such as critical thinking, problem solving, and communication. However, learning is not committing a set of facts to memory, but the ability to use resources to find, evaluate, and apply information. This paper addresses these concerns by discussing "how we learn" and reviewing the literature on what works to improve learning. It is clear that active processing of information, not passive reception of information, leads to learning. That is, students must construct their own understanding of concepts, relationships, and procedures. Teachers can encourage this process by carefully considering the type and organization of information as well as instructional strategies. Specifically, teachers should reduce the total amount of factual information students are expected to memorize, reduce our use of the passive lecture format, and devote much more effort to helping students become active, independent learners and problem solvers. Collaborative learning activities, interactive models, educational games, and establishing a culture of inquiry/scholarship are critical for achieving these goals.     

What is happening to the monocotyledons?

An attempt is made to elucidate some of the more pronounced departures from traditional classifications in the book The families of the monocotyledons byDahlgren and collaborators, which embodies the latest opinions of the lateRolf Dahlgren on the subject. Consideration is given to the treatment of theLiliiflorae (especiallyLiliales andAsparagales) andBromeliiflorae, and to the theory offered for the origin of the monocots which identifies theDioscoreales as the most primitive order of the subclass.Dahlgren aimed at an eclectic classification (one based on a combination of similarity criteria and phylogenetic criteria) and the results of his use of cladistic methods (in association withF. N. Rasumssen) to supply the phylogenetic input are assessed. The resulting system itself is considered in the light of the distinction drawn byJ. S. L. Gilmour between natural and artificial classifications and their respective uses.Dedicated to the memory of JohnS. L. Gilmour.     

Caspase-1: is IL-1 just the tip of the ICEberg?

Caspase-1, formerly known as interleukin (IL)-1-converting enzyme is best established as the protease responsible for the processing of the key pro-inflammatory cytokine IL-1β from an inactive precursor to an active, secreted molecule. Thus, caspase-1 is regarded as a key mediator of inflammatory processes, and has become synonymous with inflammation. In addition to the processing of IL-1β, caspase-1 also executes a rapid programme of cell death, termed pyroptosis, in macrophages in response to intracellular bacteria. Pyroptosis is also regarded as a host response to remove the niche of the bacteria and to hasten their demise. These processes are generally accepted as the main roles of caspase-1. However, there is also a wealth of literature supporting a direct role for caspase-1 in non-infectious cell death processes. This is true in mammals, but also in non-mammalian vertebrates where caspase-1-dependent processing of IL-1β is absent because of the lack of appropriate caspase-1 cleavage sites. This literature is most prevalent in the brain where caspase-1 may directly regulate neuronal cell death in response to diverse insults. We attempt here to summarise the evidence for caspase-1 as a cell death enzyme and propose that, in addition to the processing of IL-1β, caspase-1 has an important and a conserved role as a cell death protease.